21633956 has 6 divisors (see below), whose sum is σ = 37859430. Its totient is φ = 10816976.

The previous prime is 21633947. The next prime is 21633973. The reversal of 21633956 is 65933612.

It can be written as a sum of positive squares in only one way, i.e., 21473956 + 160000 = 4634^2 + 400^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2704241 + ... + 2704248.

It is an arithmetic number, because the mean of its divisors is an integer number (6309905).

Almost surely, 2^21633956 is an apocalyptic number.

It is an amenable number.

21633956 is a deficient number, since it is larger than the sum of its proper divisors (16225474).

21633956 is a wasteful number, since it uses less digits than its factorization.

21633956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5408493 (or 5408491 counting only the distinct ones).

The product of its digits is 29160, while the sum is 35.

The square root of 21633956 is about 4651.2316648389. The cubic root of 21633956 is about 278.6411886029.

The spelling of 21633956 in words is "twenty-one million, six hundred thirty-three thousand, nine hundred fifty-six".